Gun cartridge



s. R. CARSON GUN CARTRIDGE March 15, 1938.

Filed Aug. 15, 1934 INVENTOR 5751715 F. 551290]? BY M fl ohm. w

ATTORNE 5 Patented Mar. 15 1938 UNITED STATES PATENT OFFICE GUN CARTRIDGE Stanley R.Carson, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application August 15, 1934, Serial No. 739,911

4 Claims. (Cl. 102-12) This invention relates to gun cartridges for which is held partly within casing ID, the joint shot guns, rifles, machine guns, or any other between the two being shown at l2 in Fig. 1. type of gun. I I3 designates the hard dry lubricating coating of An object of the invention is to provide'a dry .this invention which covers all the exposed surwater-proofing and lubricating coating on the -face of projectile II and nearly all the exterior 5 exposed surface of such cartridges which facillsurface of easing I 0. The joint I 2 is more setates the insertion or ejection of the cartridge Curely l d by ting ii! to safeguard the P W- from the gun barrel and prevents sticking or 'der contents from deterioration by the action of jamming due to the cartridge being swollen or air or water.

over-sized prior to insertion in the barrel or due The lubricating material is made by first 1 to any swelling of the casing caused by the firing thoroughly dissolving pyroxylin in a suitable explosion. Any tightness of fit of the casing in solvent such as acetone and then mixing in the the gun barrel often causes jamming of the autodesired amount of very'flnely divided amorphous matic ejecting mechanism in various types of graphite to form a homogeneous mixture. The

guns, particularly automatic shot guns and maproportions by weight of the dry pyroxylin and chine guns. This difficulty has been long recoggraphite may vary from 65% graphite and 35% nized and various solutions of the problem have pyroxylin to 5% graphite and py y been proposed and tried. At the present time for best results under various conditions of usage various kinds of grease are often used on the of the lubricant material. The consistency of outside of the cartridges to prevent jamming of the fluid mixture may be regulated or made 20 automatic ejecting devices. Any kind of grease whatever desired by the amount of acetone or has the serious disadvantages of being easily other solvent used, since the solvent itself does rubbed oil. and of easily catching and retaining not form a part of the final dry lubricating coat- 7 dirt or any foreign matter which will greatly ing. The consistency should be such that the 5 interfere with the desired lubrication of the cartridges, when dipped into the liquid lubricant cartridge. mixture and then immediately allowed to drain The hard dry strongly adhering lubricating and dry, will have a dry coating I3 of the desired coating of this invention remains clean and eflithickness. Obviously the thickness of coating i3 ciently performs the desired lubricating function obtained from a single dipping will be greater if and avoids the above described defects of grease less solvent is used for a given amount of pyroxy- 3 or any sticky lubricant. lin and graphite, and less if more solvent is used.

Another object of the invention is to provide Upon the quick evaporation of the acetone the a dry lubricating coating that can be efliciently mixture of pyroxylin and graphite remain as a and simply applied to filled cartridges without uniform coating strongly bondedto the brass application of heat and hence without danger or casing Ill and projectile II. The coating on the 35 harm to the cartridge load, and which will projectile serves as a dry lubricant between the strongly adhere to the cartridge surface and will projectile and the rifling of the gun barrel.

not be rubbed or worn oil in handling. In Fig. 3 the ordinary "shot gun shell there Further objects and advantages of the present shown has a brass cap IS, a paper composition 40 invention will be apparent from the following decasing l6 and a, paper wad I! pressed against 40 scription, reference being had to the accompanythe shot I8 therein and held in place by the ing drawing, wherein a preferred embodiment of crimped end IQ of casing 16. When this comthe present invention is clearly shown. pletely loaded shell is dipped into a liquid mix- In the drawing: ture as above described the dry water-proof lu- 5 'Fig. 1 is aside elevation of a metal casing rifle brlcating coating 20 is formed .which seals the cartridge treated with the dry lubricant coating joint between the crimped and I9 and the wad of this invention. ll. Then there is provided a water proof over- Fig. 2 is a section on line 2-2 of Fig. 1 on a all coating 20 which prevents all moisture from larger scale and illustrates the relatively thin entering the paper casing and causing swelling surface coating. thereof. s lubricant coating 20 for shot gun 50 Fig. 3 is a side view, partly in section, of an shells greatly facilitates the operation of autoordinary paper shot gun shell treated with the matic shot guns, and also renders more easy the lubricant coating of this invention. manual insertion or removal of the shell in any In Figs. 1 and 2, I B is the ordinary brass castype gun. ing' and II the lead or other metal projectile While the embodiment of the present invention 5o as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows: l. A small arm gun cartridge having a metal casing and an exposed metal bullet and a strong- I ly-adhering dry lubricating and protective coating for said casing and bullet, said coating comprising a homogeneous mixture of roughly from 15 to 35 percent pyroxylin and from 85 to 65 percent very finely divided amorphous graphite.

2. A small arm gun cartridge having astrongly-adhering dry lubricating and protective coating encasing said cartridge and tenaciously bonded thereupon said coating comprising a homo geneous mixture of pyroxylin and very finely divided amorphous graphite.

3. A small arm gun cartridge having a. part metal and part paper external casing, said casing having a strongly-adhering dry lubricating and protective film coating comprising a homogeneous mixture of pyroxylin and very finely divided graphite strongly bonded to both the metallic and paper portions thereof, said coating having from 65 to 85 percent graphite content by weight.

4. A loaded shot gun shell having a paper casing crimped over a wad at the discharge end 10 thereof, said paper casing and wad having a strongly-adhering dry waterproofing and lubricating coating comprising a homogeneous mixture of pyroxylin and graphite applied thereupon after the casing is crimped over the wad, said coating having from 65 to 85 percent graphite content by weight.

STANLEY R. CARSON. 

